Gas pressure apparatus



li u

July u? 1933,

P. E. KLQPSWEG lGAS PRESSURE APPARATUS Filed May 1l, 1929 2 Sheets-Sheet l Patented Julyv 11., A

UNITED 1 STATES PATENT iol-FICE PAUL n xnorsrne, or cnIcAeo, ILLI'noIs', Assrenon 'ro CENTRAL SCIENTIFIC comrANY, or CHICAGO, ILLINoIs, A conronArIon or ILLINOIS GAS PRESSURE APPARATUS Application led May 11, 1929.- Serial No. 362,343.

This invention relates to gas pressure apparatus and has, among its principal objects, to provide devices especially suited for Boyles law and Charles law demonstrations with which the average student can easily obtain the necessary data, and'which will withstudents; that can be easily stored and maintained; that'will give results suiiiciently close to theoretical laws to be convincing; and that will be free from difficult adjustments and manipulations, thereby giving the student more time for productive work and permitting alarger number .of students to handle the apparatus within a given period.

Further objects and advantages of the invention will be vrevealed as the disclosure proceeds and the description is read in connection with the accompanyingdrawings, in which Fig. l is a front elevation of the preferred form of the device for use in connection with Boyles law demonstrations, the intermediate portion and the two legs of the tripod being broken away;

Fi 2 is a side elevationof the same, looki inv rom the right in Fig. 1; 1g

3 is an enlarged sectional view taken on the line 3-8 of Fig. 2;

Fig. 4 is a transverse sectlonal view taken on the line 4--4 of Fig. 3;

Figs. 5, 6 and 7 are lsimilar diagrammatic i views illustrating the mercury heights in the two arms of the J-tube, corresponding to different pressures of the gas under treatment;

F1g.` 8 (Sheet 2) is a side elevation 'correy s @riding to Fig. 2 (sheet 15er a' modified orm especially adapted for' Charles 'law demonstrations; fv Fig. 9 is a front elevation with the bulb and Fig. 8;

Fig. 10 is an enlarged sectional view on the line 10-10 of Fig. 8, .and 'corresponding' to Figz; and

g 11 is an enlrged. sectional of` portion ofthe volume "arm illustrating. the

preferred manner of providingfa visible vol-i ume limit in a. metallic tube.

But these specific illustrations-andthe corcolumn bracket 29, includin .30 anda vertical arm 31 reen? set 32. .The adjacent surface of the flanges 28 and 30 are ground and shellacked so that vwhen clampedto'gether by the screws33 they responding description are used here solely for the purpose of disclosure and it is realized that thesubstance of the invention mayv be embodied in other forms and put to other uses', and it is intended that all such changes shall be covered by the claims. stand the mishandling to be expectedfrom Boyles Zacv device (Sheet l) corrosive material, and having-therein a merv cury chamber 12 open at one side which is closed by a diaphragm 13 clamped'and shellacked to a ground surface 14 on Vthe body by screws 15 and a base flange 16 of a cap^17 The central portion of this cap is thickened` and threaded at 18 to receive a screw 19, having a ball point 20 to cooperate with the wear plate 21 at the center of the diaphra on the outside. The natural resiliency o the diaphragm is augmented by a spring 22'seated in an annulai` p'ocket 23 in the cistern body and bearing against a wear plate 24 at the lcenter of the diaphragm on the inner side. d

Adjacent to the upper end of the mercury chamber the cistern body is drilled horizontally at 25 and vertically at 26 to form a passage communicating with the cistern; and -in this preferred form 25 extends fromfside to side of the cistern body, one :end or outlet being closed by a. plug 27.

'zo'I At the top the cistern body is provided with a flange 28 which forms a seatfor a orced by a gusform va mercu -tight joint.

a base flange The interme late portio'nsof the adjacent surfaces of the flanges 28 and 30 are grooved',

as indicated at 34vand 35, which grooves ycooperate to forma passage 36. 1 Anupright'wooden column 37 is screwed to theyarm 31, and a scale bar `38 is secured on the-front of the column. On4 the left of `the scale bar a. glass tube 3 9, having its upper 'end 40 closed, is made fast-'by suitable clips 41,

and its lower end is cemented in a. bore or outlet 42 communicating with one end of the passage 36. On the right of the scale bar, andsecured by the same, or similar clips 41, is a glass tube 43 having its upper end 44 open, and its lower end cemented in a bore or outlet 45 communicating with the opposite end of the passage 36. The two glass tubes in conjunction withthe passage 36, form a J-passage, of which the tube 39 is the short, or volume arm, and' the tube 43 is the long, or manometer arm. The joints between tubes 39 and 43 and the bores 42 and 45 must, of course, be mercury-tight, which may be insured by using a secret preparation known in the trade as de Kotinsky cement.

It will, of course, be understood that any other suitable means may be employed for making a mercury tight seal between the tubes 39 and 43 and the bores 42 and 45, re-

l spectively.

' The scale bar is graduated in any suitable units, that illustrated being in, centimeters and corresponding to about eighty centimeters in length.

The sides of the column 37 are grooved at 46 to receive resilient fingers 47 of a frame` 48 equipped with a crystal 49 and a hair line 50, to facilitate reading the height of the mercury in the two arms of the tubes.

The apparatus constructed and assembled substantially as shown in Figs. 1 to 4 may be filled at the factory and received by the pur- Chaser ready for use.1 The escape of mercu during handling and shipping may be e fectually prevented by winding alittle cotton on a wire inserted in the manometertube 44. The wire should, of course, project beyond the tube in order` that the cotton may be readily extracted when the apparatus is to be put in use.

It will be clear that turning the screw 19 to deflect the diaphragm 13 to the left in Fig. 3 will cause mercury to How from the cistern chamber 12 through the passage formed by the drillings 25 and 26 to the J-passage; that turning the screw in the reverse direction to relax the diaphragm will permit a low in the opposite direction, and that in each case the mercury will assume elevations in the respective arms 39 and 43,

. in accordance with Boyles law. y

Readings maybe taken for successively decreasing volumes, as illustrated by 7 0, 57 and 40 (Figs. 5, 6 and 7), or for successively increasing volumes, or, for better accuracy, readings may be taken both Ways.

Charles Zafw (Ze/vico (Sheet Z) I The tripod base 10, the cistern body 11 with appurtenances including the bracket 29 may be, and preferably are, identical with those that the plug 27 is removed from the bore 25 andinserted in the bore 42.

The column 37 is replaced by a similar column 51, equipped with a suitable scale bar 52, and a glass tube l53, corresponding to the tube 43, on Sheet l, in structure and function.

The volume arm of the J-passage in this instance vpreferably includes a heavy steel tube 54 threaded into the bore 25, a lighter steel tube 55 andl a steel bulb 56. The tube 54 is bent at right-angles and is joined to the tube 55 by a coupling 57 just above which the tube-55 extends through and is soldered to the neck 58 in the bottom 59 ot' a copper vessel 60, which encloses the bulb 56, and is adapted to be lled with a cooling or heating fluid, as occasion may require.

The pipe 55 is bent laterally at 6l in Vorder to place the bulb 56 at one side of the vessel 60 and thereby provide space for an electrical heating device 62, or for ice, or other things used in changing the temperature otthe gas within the bulb 56. The vessel 60 is provided With a hose nipple 63 in the bottom` and with a screw cap 64' also provided with a. hose nipple 65. It is supported by clamps 66 attached to the column 37 at 67.

A glass tube 68 providedwith anetehed mark 69 is inserted in and cemented to the upper end of the tube 54, and a portion of the wall of that tube is cut away at 70 to make a short length of the glass tube, including the mark 69, visible, and this result is promoted by an oppositely disposed opening, or Window 70B. f

All the volumetric content of the tubes 54. 55 and 56, above the mark 69, becomes the constant volume chamber for the gas to be studied. A bent rod 55"L in the. tube 55 reduces its volumetric capacity Without matexially alfecting free passage through thel tu e.

In use, after thegas in bulb 56 has been brought to a selected temperature, the screw -19 is adjusted to bring the mercury to the line l69 in the tube 54, when the mercury elevations in the two arms are read on the scale 52. In the case of the volume arm this is facilitated by a small triangle, or the like, held Awith the edge over the line 69, and extending across the scale 52.

The temperature of the gas in the bulb 56 is then changed by any suitable means,`an-

other adjustment of the mercury madc,.and

other readings taken from the scale.

The metal wall of the bulb assists in bringing the contained gas to the temperature o the surrounding medium with little or no more lag| than is to. be found in the thernunneter, hence, no error of consequence is committed. v

For hightemperature readings the vessel 60 may be wrapped with suitable insulating material to' reduce convection.

the loss by radiation and 1 If the method of two fixed points is to be used the screw cap 64 is equipped with a steam hose and a clamp, and the vessel is filled with ice.

lt will be readily noted that all rubber connections, common to apparatus heretofore used, have been eliminated, and-the contami-4 nation of mercury by sulphide formation thereby'obviated. Mercury comes in contact lar means including a closed volume arm, an

with metal or` glass alone, and leakage is almost entirely eliminated. Both the devices maybe easily and quickly prepared for shipping with appropriate quantity of mercury contained, and as easlly and quickly prepared for use upon receipt. They are compact, comparatively unbreakable, and,

therefore, simplify the storage problem and reduce the upkeep due to mishandling.

` The mercury levels are easily adjustld t e screw which is convenient to the hand of the operator facing the scale. For convenience this motion may be designated as micrometric, though, of course, it is not to be construed within the strict meaning of that term as applied to optical and similar apparatus. About forty threads to the inch on the screw 19 gives all the precision required for ordinary purposes.

l claim as my invention:

l. ln a device of the class described, tubuopenfmanometer arm, said 'arms being structurally separate, a metallic cistern closed eX` cept for a passage directly connecting with,

said means and forming a connection between said arms, and micrometric means for varying the capacity of the cistern.

2. ln a device of the class described, a

cistern body having a iiuid chamber on one side thereof, with a resilient diaphragm wall, means for flexing said diaphragm `wall to vary the Huid capacity of the chamber, and resilient means for engaging the inner side of said diaphragm forholding the same in continuous engagement with said first-named means. Y y

3. ln a device of the class described, a cistern member having a cistern therein, a passage formed in said member connecting with the cistern, tubes for indicating the liquid levels opening into said passage, a diaphragm closing said cistern and forming a exible Vwall therefor, a guide pin extending along the axis of the cistern normal to-said diaphragm, a helical spring for pressing said diaphragm outwardly, a micrometric screw in substantial alignment with said pin and bearing upon the outer side of said diaphragm to deflect the diaphragm against the said body being provided with passages comy* municating with two outlets adapted to al` -low the insertion of closed volume arms therein, oneof said outlets being provided in the upper face of said cistern body whereby a closed volume arm may be attached parallel to said scale and form with said apparatus a Boyles law device,`the other of said outlets being provided in the rear face of said cistern body, whereby a closed volume arm bearing a considerably enlarged volume chamber may be attached to said apparatus and form therewith alaw of Charles device, and means for closing either .one or the other of said openings.

5. tallic cistern body having a storage chamber therein and having a` passage connecting the chamber with two outlets, a metallic diaphragm closing the chamber, means for flexing the diaphragm' to vary the capacity of the chamber, and a pair of rigid tubular members mounted one in each of said outlets, one

m/ovable relative to the-base to change the volumetric capacity of the recess and force fluid into said arms.

r 7. ln a device of the class described, a metallic base provided with a recess in one ofits faces to receive a fluid and having pas sages connecting the recess with two outlets to thereby form a passage through the base, a rigid open'manometer arm mounted in one of the outlets, a rigid volume arm mounted 'in the other outlet, a metallic bulb on the end of the volume arm, a vessel enclosing the bulb, ametallic diaphragm closing the recess, and means for flexing the diaphragm to force duid into said arms and compress a gas in the bulb.

8. ln a device of the class described, a body made of material that will not chemicallyV attack or contaminate mercury and having a recess in one of itsfaces for receiving a fluid and a passage for connecting the recess to two outlets, an upright column rising from the body, a. scale on the front ofthe column, a rigid manometer tube mounted in one of the outletsand supported by the column, a rigid lll) and a second horizontal passage adapted to connect with two outlets a closure for the recess movable relative to the base to change the volumetric capacity of the recess, vand micrometric means for moving the closure.

l0. In a device of the class described, a cast metal base provided with a recess in one of its faces for receiving a fluid, said base also being provided with two outlets and drilled horizontal and vertical passages conl a closure for the recess movable relative to' the base `t-o change the volumetric capacity of the recess, and micrometric means for movino' said closure, said base being cast in a singige piece.

11. In a device of the class described, a base made of material that will not chemically attack or contaminate mercury and being provided with a recess in one of its faces to receive a fluid and having passages connecting the recess with two outlets to thereby form a passage through the base connecting the two outlets toeach other and to the recess, a closure for the recess movable relative to the base to change the volumetricv capacity of the recess, and micrometric means for moving the closure.

In testimony whereof I aiiX my signature.

PAUL E. KLOPSTEG. 

